Hydraulic hammers are used on work sites to break up large hard objects before such objects can be moved away. Hydraulic hammers may be mounted to back hoes or excavators, or may be hand-held. Typically, the hammer assembly is powered by either a hydraulic or pneumatic pressure source. During a work or power stroke, high fluid pressure is applied to a first shoulder of a piston, thereby driving the piston in a forward direction. The piston then strikes a work tool, commonly referred to as a tool bit, which is driven in the forward direction thereby causing a work tip of the work tool to strike the rock, concrete, asphalt or other hard object to be broken up. During a return stroke, fluid pressure is applied to a second shoulder of the piston in order to return the piston to its original position.
The work tool is retained within a sleeve, commonly referred to as a front head. Conventionally a tool retention pin is used to retain the tool within the front head. The pin extends across one side of the front head and engages with a transverse machined groove in the tool. The height of the groove is greater than the diameter of the pin, thereby allowing reciprocal forward and backward movement of the hammer over a limited range of movement. In use, when the work tip does not fully engage with the hard object on which the tool is being used, or during an idle stroke, the front head must resist the work stroke of the tool. This results in a large impact load, which causes high instantaneous stresses in the components which transfer the impact load back to the hammer body.
At least some of the disclosed embodiments may overcome one or more of the abovementioned drawbacks.